IT WAS A DAY of reckoning for Radovan Karadzic, the Bosnian Serb war criminal, and a day of reckoning for me.

On March 24, I stood outside the United Nations war crimes tribunal in The Hague, surrounded by dozens of men and women who had survived massacres and concentration camps and rapes during the Bosnian war. I had joined the gathering on Churchillplein before the announcement of the tribunal’s verdict for Karadzic, who was charged with genocide and crimes against humanity. I noticed a female security officer from the U.N. weaving back and forth through the crowd, trying to reach me. I realized, as the officer grabbed for my wrist and tried to put handcuffs on me, that my freedom was at issue on this day, too.

“She’s crazy, she has no jurisdiction,” I shouted at a Dutch police officer who stood before me stone-faced. I didn’t try to run. I was on Dutch territory so I assumed the Dutch police would not allow a U.N. officer to arrest me. Having no police powers, the International Criminal Tribunal for the former Yugoslavia had always depended on member nations to execute its warrants — but this was about to change. Ironically, the tribunal’s first arrest by one of its own officers was going to be of a journalist who had reported on warlords and mass killers, rather than an actual war criminal.

Within the time it took to do an interview on Croatian television recounting the U.N. security officer’s initial and failed attempt to arrest me, backup from the tribunal had arrived. I understood what was happening when the Bosnian survivors around me began to yell, “She’s ours, we won’t let you take her away.” I was in the middle of the fray, protected by the already-martyred bodies of women and men who had come to receive justice from the very same tribunal they were now opposing by trying to defend me. I was ashamed, angry, shocked.

During the 1990s, I was at Le Monde and reported for the French newspaper on the wars in the former Yugoslavia. Then I served for six years as the spokesperson and Balkan adviser for Carla Del Ponte, the tribunal’s chief prosecutor. In a book I published in 2007, and an article in 2008, I criticized and, contrary to other journalists, named the tribunal judges who had improperly and unlawfully struck a deal with Serbia aimed at denying victims of mass atrocities access to information critical to their ability to obtain reparations for crimes committed against them and their relatives. In 2008, the tribunal indicted me for disclosing confidential information and eventually convicted me of contempt of court, levying a fine of 7,000 euros. It was a strange case that, in the words of a prominent American law professor, consisted of me being prosecuted by the tribunal for “accurately describing two of its boggled decisions.”

As with the trials of Chelsea Manning and other whistleblowers, it was of little legal interest that the divulged information was unquestionably of public interest and kept confidential primarily to conceal its unlawfulness. Sure, some of the passages of my book, Peace and Punishment: The Secret Wars of Politics and International Justice, had irritated various governments. Some British political personalities threatened me with defamation suits if I didn’t modify the passages concerning them. I didn’t comply, and they never pursued legal action. The truth isn’t defamatory; it’s the truth. But the judges at the tribunal had a more effective weapon against freedom of expression: prosecuting me for contempt of court. It is a procedure they created themselves, in which they were both judge and jury. And in this case, they were also the interested party.

With the hope of finding an effective remedy before an independent court, I had invited the ICTY to withdraw the fine from an account I set up in in France. The procedure leading to my condemnation was tarnished by countless irregularities, so I believed a French judge would undoubtedly refuse to validate the payment of the fine. In response, the ICTY judges preferred to declare the fine unpaid, and converted the punishment to seven days of prison, accompanied by an international arrest warrant. It was the end of 2011. For five years, neither the authorities in France nor the Netherlands — the two countries the ICTY had called upon to arrest me — came to put me in handcuffs. During that period, I visited three continents and presented my passport hundreds of times at various borders. I never worried.

My visit to The Hague for the Karadzic verdict was the third time I’d returned to the capital of international criminal justice since the ICTY issued my arrest warrant. My surprise was complete. Soon after the first attempt to arrest me, U.N. security officers, under the escort of the Dutch police, tore me from the crowd and led me brusquely to the door of the tribunal. It was a bit after 12:30. I was in a cell in the basement of the court building when the Karadzic judgment (40 years) was read out. The black van that earlier in the day had brought Karadzic to the tribunal from its prison in nearby Scheveningen was, I am sure, the same one I was put into with handcuffs on my wrists. It took me to the prison of war criminals, sowers of death across the Balkans and the African continent, to serve my sentence.

The Detention Unit for international war criminals in the Scheveningen neighborhood of The Hague, Netherlands, July 22, 2008.

Photo: Fred Ernst/AP

Located near the large beach in Scheveningen, in the suburbs of The Hague, the United Nations’ Detention Center is a veritable five-star prison at unbeatable rates, offering fully equipped kitchens for inmates, TVs in their cells, no cockroaches or mice, and a decent fitness center. But it’s still a prison, and I teetered on the edge of despair in my first hours of incarceration. The humiliation of being strip-searched, standard procedure for prison intake. The cynicism of the agent who rifled through my personal effects with gloved fingertips, taking an inventory thereof and ultimately leaving me five lipsticks and a nail file (moisturizer wasn’t allowed). The vision of that narrow bed in my cell, with that miserable brown faux leather mattress where the perpetrators of genocide had slept in denial. And the very thought that I now shared with them a feeling of revolt against the confinement of prison horrified me. During my medical exam at intake, I had warned the doctor who asked me about potential allergies: “Only injustice, doctor.”

I was placed on suicide watch, a measure as incomprehensible to me as to the guards, which forced me to take sleeping pills for the first time in my life. I had to keep a light on the whole night so the guards would settle for opening the small hatch to survey the inside of the cell every 30 minutes, rather than entering my cell twice an hour and turning on the fluorescent light themselves. We had a good laugh, the guards and I, when, on the third day of my confinement, the president of the International Criminal Tribunals forked over a letter dismissing my request to suspend around-the-clock monitoring under the pretext that “Ms. Hartmann has a light switch in her room and can turn the light on and off as she wishes.” I suppose it would have been hard for him to pretend that I was suicidal.

The interior of a cell in the Scheveningen prison.

Photo: Jasper Juinin/AFP/Getty Images

I was incarcerated for carrying out my work as a journalist, and so the tribunal subjected me to strict isolation measures, intended to keep me from performing my trade from within the prison. The president of the tribunals, Judge Theodor Meron, didn’t hide that the key argument behind his decision to ban me from “mix[ing] with the rest of the detainees” was that “Ms. Hartmann is a journalist who has published several works on the former Yugoslavia.” Put plainly, I speak the language of the majority of the detainees, and I had come across them in the 1990s, when they had power over the life or death of their neighbors. “She [could] use her conversation or observations in her future publications, interviews, and news articles,” the judge warned.

I was prohibited from walks or any outdoor activities; if you want to have a breath of fresh air at Scheveningen, better to be a bloodthirsty executioner than accused of a crime of lèse-majesté. I frequented the prison’s fitness center every day to compensate for the prohibition on going outdoors (the reason for which I was not informed while in prison). From the window in front of the treadmills and elliptical machines, I saw other inmates taking the air on the tennis courts under the open sky. Sporting a cap and sometimes sunglasses, Gen. Ratko Mladic, the butcher of Srebrenica, walked escorted by a guard whose tracksuit made him look like a sports coach. And the great Abou Tourab, alone in the middle of the sports field, who seemed to be growing bored. Under his real name, Ahmad Al Mahdi Al Faqi, the former chief of the Islamic Police in Timbuktu is accused before the International Criminal Court of having destroyed a dozen historic and religious sights in 2012. Then there’s Slobodan Praljak, former theater director turned Croatian Army general, whose treatment of Muslims in western Bosnia and Herzegovina in the 1990s got him 20 years of prison for crimes against humanity; he preferred a nice walk and floor exercises.

I wouldn’t have the “privilege” of treading upon the same ground. As per the guards’ orders, I was only permitted to breathe fresh air in the lucht kooï — the air cage — located on the roof of the prison, to which I was escorted via a narrow service staircase. A meter of sky breaks through the bars and I took in the flight of gulls arriving from the nearby North Sea. It is a sinister spot, with brick walls on which, since the 1970s, prisoners had scratched their names and countries of origin, but it was suitable for fact-checking sessions with the guards; nothing kept me from accurately informing my jailers. There, I took full advantage.

The guards were told that I was a former prosecution spokesperson who was arrested over an unpaid fine for publishing secret court information. A half-truth is a whole lie, as the saying goes. I explained to them that it was not as a former tribunal employee that I was alleged to have breached confidentiality rules. The judgment and the charge alike were unambiguous, I noted: It was as a journalist who published a book that criticized judges at the tribunal, and exposed the legal reasoning behind a controversial decision to hide information, that I was behind bars.

I did my best to distract them with anecdotes of tracking fugitives, back when I worked alongside the chief prosecutor, or stories of my encounters with the prison’s other inmates during the war in the former Yugoslavia, when I was a journalist for Le Monde. I had met Karadzic before he became a warlord: I was at the Holiday Inn in Sarajevo when he established his headquarters there in 1992 to prepare his war against non-Serbs in Bosnia. Later I followed him to Pale, the de-facto capital of his kingdom, where he constructed his puppet state on the ground he had drenched in his victims’ blood. I followed him until 1993, when he denied me access to the territory he controlled because he disliked my articles describing the atrocities he had ordered.

My little stories were, in fact, only a pretext to explain the circumstances of my arrest and why I was there. The guards, even the most unyielding among them, remained attentive until the end, their manner one of vexation. Inevitably, one after another concluded with a line like, “Life can be unjust, that’s the way it is.” Their indignation touched me, their resignation, ineluctable as it was, moved me to despair.

Florence Hartmann appears before the ICTY in The Hague.

Photo: Olaf Kraak/AFP/Getty Images

I was arrested on the Thursday before Easter; the holiday weekend must have seemed long to my guards, very long, isolated on a floor where I was the sole detainee, locked in my cell from 5:30 p.m. until 9:00 a.m. On the sixth day of my incarceration, March 29, they were on the lookout for news of a possible early release. They were convinced that their daily reports of my exemplary conduct would permit me to spend my sixth and last night at an address of my choosing. Only one war criminal condemned by the ICTY had ever served more than two-thirds of their sentence.

At 12:30 p.m., the guards came to close the door to my cell for one hour, like every day. It seemed that in 24 hours, I would have served my full seven days in prison — not for genocide, nor crimes against humanity, but for the crime of opinion! In the early afternoon, still no information on my release, neither from the prison administration, nor from my lawyer or my embassy. It was a bad sign. I hadn’t planned out my half-hour in the lucht kooï yet when, at 2:30 p.m., a guard entered my cell to inform me that the French consul and an attaché from the embassy were coming to see me. I gathered my laundry, which I’d hung out to dry in the common room — a space that, given the absence of company, I had only entered to make myself a coffee or to heat up the contents of microwaveable containers that served as a meal.

At 3 p.m., the guard assigned to escort me downstairs to meet with my visitors said, “You’re leaving, pack your belongings immediately.” I was ready within a few minutes and rushed to the telephone located on the other wing of my floor. I discovered that the French consul was in fact not given visitation authorization for that day, and so never moved from her post in Amsterdam. As I waited for the return of the possessions that had been seized during intake, I watched the guards put away the tables, the coffee machine, the trash cans on my floor. The tragi-comedy is over, the set crew can remove the scenery. Suddenly, it all seemed unreal. A bad dream.

The courtyard in front of the prison in Scheveningen was deserted when I was finally released. The taxi my lawyer sent for me took me to a friend’s house; I waited for her outside in the sunlight. She’s a journalist, and apologized for having to wrap up her dispatch on my release before she could bring me her keys. (With no advance notice of my release, the tribunal had made sure the media would not be waiting for me outside the prison.) It was only when I turned on my cellphone and discovered hundreds of messages and missed calls that I realized how cut off I had been from the world.

I left The Hague and returned to Paris with an even stronger feeling of anger and injustice than when I was in jail. Although Karadzic had been convicted, a man who had been incarcerated for a while on the very same floor as I was incarcerated — Vojislav Seselj — was acquitted by the tribunal. Seselj, an ultra-nationalist Serb, had recruited and armed paramilitaries that were blamed for atrocities in Croatia and Bosnia, and he had galvanized them with incendiary hate speeches. But the tribunal judges — one of them a French national — ruled that Seselj was expressing his political opinion in an attempt to boost the morale of his followers, rather than calling for ethnic cleansing. My words against the tribunal had amounted to a crime, whereas Seselj’s calls for killing and revenge against non-Serbs amounted to free speech. I heard about the Seselj verdict while on the same spot where I had been arrested a week earlier. It was another brutal farce and an additional stab in the back for those still waiting for justice.